Heparin-induced DRESS syndrome in a paediatric patient and successful anaesthetic management in cardiovascular bypass surgery: case report.

BACKGROUND: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Syndrome is a severe adverse drug reaction marked by delayed hypersensitivity reactions causing skin and systemic complications. DRESS diagnosis is challenging due to the variety of clinical presentations and symptom overlap with other conditions. The perioperative period in these patients requires precise pharmacological strategies to prevent complications associated with this syndrome. The treatment of DRESS induced by unfractionated heparin during cardiopulmonary bypass (CPB) surgery presents some challenges that must be considered when selecting an anticoagulant to avoid side effects. In this case, bivalirudin, a direct thrombin inhibitor, is indicated as an alternative to heparin in patients undergoing CPB. However, in contrast to heparin/protamine, there is no direct reversal agent for bivalirudin. CASE PRESENTATION: We report the case of an 11-year-old male diagnosed with native aortic valve endocarditis and thrombosis in his left lower extremity. During valvular replacement surgery, systemic unfractionated heparin was administered. Postoperatively, the patient developed fever, eosinophilia and pruritic rash. Warm shock and elevated alanine transaminase (ALT) and aspartate transaminase (AST) levels followed, leading to the diagnosis of DRESS syndrome. Treatment with methylprednisolone resulted in complete resolution of symptoms. Seven years later, the patient was readmitted due to insufficient anticoagulation and a thrombus in the prosthetic aortic valve, presenting a recurrent DRESS episode due to the administration of unfractionated heparin, which was later replaced with low-molecular-weight heparin during hospitalization. Treatment with corticosteroids and antihistamines was initiated, resulting in the resolution of this episode. Ultimately, the patient required the Ross procedure. During this intervention the anticoagulation strategy was modified, unfractionated heparin was replaced with bivalirudin during the procedure and fondaparinux was administered during the postoperative period. This resulted in stable transaminases levels and no eosinophilia. CONCLUSION: The severity of DRESS Syndrome underscores the importance of early recognition, heightened monitoring, and a comprehensive approach tailored to each patient's needs. This particular case highlights the significance of this approach and may have a substantial clinical impact since it provides alternatives to heparin, such as bivalirudin and fondaparinux, in the anticoagulation strategy of CPB for patients who have a hypersensibility reaction to this medication; thus, enhancing clinical outcomes by minimizing risks linked to adverse drug reactions.

Mortality and major postoperative complications within 1 year after vascular surgery: a prospective cohort study.

INTRODUCTION: Patients undergoing vascular procedures are prone to developing postoperative complications affecting their short­term mortality. Prospective reports describing the incidence of long­term complications after vascular surgery are lacking. OBJECTIVES: We aimed to describe the incidence of complications 1 year after vascular surgery and to evaluate an association between myocardial injury after noncardiac surgery (MINS) and 1­year mortality. PATIENTS AND METHODS: This is a substudy of a large prospective cohort study Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION). Recruitment took place in 28 centers across 14 countries from August 2007 to November 2013. We enrolled patients aged 45 years or older undergoing vascular surgery, receiving general or regional anesthesia, and hospitalized for at least 1 night postoperatively. Plasma cardiac troponin T concentration was measured before the surgery and on the first, second, and third postoperative day. The patients or their relatives were contacted 1 year after the procedure to assess the incidence of major postoperative complications. RESULTS: We enrolled 2641 patients who underwent vascular surgery, 2534 (95.9%) of whom completed 1­year follow­up. Their mean (SD) age was 68.2 (9.8) years, and the cohort was predominantly male (77.5%). The most frequent 1­year complications were myocardial infarction (224/2534, 8.8%), amputation (187/2534, 7.4%), and congestive heart failure (67/2534, 2.6%). The 1­year mortality rate was 8.8% (223/2534). MINS occurred in 633 patients (24%) and was associated with an increased 1­year mortality (hazard ratio, 2.82; 95% CI, 2.14-3.72; P <0.001). CONCLUSIONS: The incidence of major postoperative complications after vascular surgery is high. The occurrence of MINS is associated with a nearly 3­fold increase in 1­year mortality.

Intraoperative Inspiratory Oxygen Fraction and Myocardial Injury After Noncardiac Surgery: Results From an International Observational Study in Relation to Recent Controlled Trials.

BACKGROUND: Two trials reported that a high inspiratory oxygen fraction (F io2 ) does not promote myocardial infarction or death. Observational studies can provide larger statistical strength, but associations can be due to unobserved confounding. Therefore, we evaluated the association between intraoperative F io2 and cardiovascular complications in a large international cohort study to see if spurious associations were observed. METHODS: We included patients from the Vascular events In noncardiac Surgery patIents cOhort evaluatioN (VISION) study, who were ≥45 years of age, scheduled for overnight hospital admission, and had intraoperative F io2 recorded. The primary outcome was myocardial injury after noncardiac surgery (MINS), and secondary outcomes included mortality and pneumonia, all within 30 postoperative days. Data were analyzed with logistic regression, adjusted for many baseline cardiovascular risk factors, and illustrated in relation to findings from 2 recent controlled trials. RESULTS: We included 6588 patients with mean age of 62 years of whom 49% had hypertension. The median intraoperative F io2 was 0.46 (5%-95% range, 0.32-0.94). There were 808 patients (12%) with MINS. Each 0.10 increase in median F io2 was associated with a confounder-adjusted increase in odds for MINS: odds ratio (OR), 1.17 (95% confidence interval [CI], 1.12-1.23; P < .0001). MINS occurred in contrast with similar frequencies and no significant difference in controlled trials (2240 patients, 194 events), in which patients were given 80% vs 30% oxygen. Mortality was 2.4% and was not significantly associated with a median F io2 (OR, 1.07; 95% CI, 0.97-1.19 per 0.10 increase; P = .18), and 2.9% of patients had pneumonia (OR, 1.05; 95% CI, 0.95-1.15 per 0.10 increase; P = .34). CONCLUSIONS: We observed an association between intraoperative F io2 and risk of myocardial injury within 30 days after noncardiac surgery, which contrasts with recent controlled clinical trials. F io2 was not significantly associated with mortality or pneumonia. Unobserved confounding presumably contributed to the observed association between F io2 and myocardial injury that is not supported by trials.

Association between emergency department length of stay and adverse perioperative outcomes in emergency surgery: a cohort study in two Colombian University hospitals.

BACKGROUND: In low- and middle-income countries emergency surgery represents a higher proportion of the total number of surgeries and is associated with greater morbidity/mortality. Study aims were to determine if emergency department length of stay (ED-LOS) was associated with adverse perioperative outcomes and if such association varied across patient's risk categories. METHODS: A retrospective cohort study was conducted of adult patients who underwent orthopedic or abdominal emergency surgery at two Colombian University hospitals. The population comprised a mix of a representative sample of eligible cases, with unselected patients (2/3), enriched with a high-risk subset (1/3). ED-LOS was defined as the interval between emergency department arrival and surgery start time. Our primary outcome was an adverse perioperative outcome during hospitalization, which was a composite of in-hospital mortality or severe complications such as major cardiovascular adverse events, infection, renal failure and bleeding. RESULTS: Among 1487 patients analyzed, there were 519 adverse perioperative outcomes including 150 deaths. In the unselected sample (n = 998) 17.9% of patients presented an adverse perioperative outcome with a mortality of 4.9%. The median ED-LOS was 24.6 (IQR 12.5-53.2) hours. ED-LOS was associated with age, comorbidities and known risk factors for 30-day mortality. Patients developing an adverse perioperative outcome started surgery 27.1 h later than their counterparts. Prolonged ED-LOS increased the risk of an adverse perioperative outcome in patients without risk factors (covariate-adjusted OR = 2.52), while having 1-2 or 3+ risk factors was negatively associated (OR = 0.87 and 0.72, respectively, p < 0.001 for the interaction). CONCLUSION: Prolonged ED-LOS is associated with increased adverse perioperative outcome for patients without risk factors for mortality, but seems protective and medically justified for more complex cases.

Comportamiento de la rigidez arterial en diferentes condiciones clínicas utilizando el método oscilométrico / Behavior of arterial stiffness in different clinical conditions using the oscillometric method

Resumen El estudio de la rigidez arterial, en los últimos años ha sido de gran interés en la comunidad científica, siendo un indicador importante de riesgo cardiovascular y de mortalidad, además es un predictor de progresión para ciertas enfermedades crónicas. Con el fin de comprender la interpretación de la medición de la rigidez vascular, se describen 12 casos de pacientes con diferentes condiciones fisiopatológicas, que reflejan la práctica clínica diaria, en los que se evaluó la rigidez arterial mediante un método oscilométrico (Arteriograph®, TensioMed, Budapest-Hungría, Ltd.), calculando la velocidad de onda de pulso, presiones arteriales periféricas y centrales, presión de pulso, e índices de aumentación. La medición e interpretación adecuada de esta información puede ayudar a entender y resolver dudas frente a diferentes condiciones fisiopatológicas asociadas a las enfermedades cardiovasculares, mejorando la toma de decisiones terapéuticas, el seguimiento de pacientes y optimizar la prevención cardiovascular.

Abstract The study of arterial stiffness has been in recent years of great interest in the scientific community, being an important indicator of cardiovascular risk and mortality, in addition to being a predictor of progression for certain chronic diseases. In order to understand the interpretation of the measurement of vascular rigidity, 12 cases of patients with different physiopathological conditions are described, thus reflecting the daily clinical practice, in which the arterial stiffness was evaluated by means of an oscillometric method (Arteriograph®, TensioMed , Budapest-Hungary, Ltd.), calculating the pulse wave velocity, peripheral and central arterial pressures, pulse pressure, and augmentation indices. The adequate measurement and interpretation of this information can help to understand and resolve doubts in the face of different physiopathological conditions associated with cardiovascular diseases, improving therapeutic decision-making, following-up of patients and optimizing cardiovascular prevention.

Histidine-Tryptophan-Ketoglutarate Solution versus Blood Cardioplegia in Cardiac Surgery: A Propensity-Score Matched Analysis.

BACKGROUND: Choosing a cardioplegic solution is a significant issue in modern cardiac surgery. Although different options are available, the optimal strategy for myocardial protection has not been established. The aim of this study was to compare intraoperative and postoperative effects of histidine-tryptophan-ketoglutarate (HTK) solution with those of standard blood cardioplegia with St Thomas No 2 solution. The study was conducted using a large cohort of adult patients undergoing complex cardiac surgery. METHODS: This study was a single center retrospective review of prospectively collected data. Between January 2008 and December 2015, 4480 patients underwent cardiac surgery using cardiopulmonary bypass (CPB) and cardioplegic arrest. Patients were divided into a blood cardioplegia group (n = 3852) and an HTK solution group (n = 628). Propensity score matching was used to adjust for differences between the two groups, and 292 matched pairs were identified. The primary end point was Intensive Care Unit (ICU) length of stay (LOS). Secondary end points included intraoperative changes in serum sodium concentration, readmission to ICU, transfusion of blood products, 30-day hospital readmission, 30-day mortality, and the incidence of major postoperative complications. Results: No significant differences were found between the matched groups with regard to baseline characteristics. Aortic cross-clamp and CPB times were longer for the blood cardioplegia (147.4 versus 132.8 min; P < .001). Administration of HTK solution was associated with acute and transient hyponatremia (141 versus 130 mmol/L; P < .001). ICU LOS was comparable between the groups (5.4 versus 5.4 days; P = .585). No significant differences were noted in any other secondary end point. CONCLUSIONS: During complex cardiac surgery, both cardioplegia techniques were equivalent in terms of early clinical outcomes.

Myocardial Injury After Noncardiac Surgery (MINS) in Vascular Surgical Patients: A Prospective Observational Cohort Study.

OBJECTIVE: To determine the prognostic relevance, clinical characteristics, and 30-day outcomes associated with myocardial injury after noncardiac surgery (MINS) in vascular surgical patients. BACKGROUND: MINS has been independently associated with 30-day mortality after noncardiac surgery. The characteristics and prognostic importance of MINS in vascular surgery patients are poorly described. METHODS: This was an international prospective cohort study of 15,102 noncardiac surgery patients 45 years or older, of whom 502 patients underwent vascular surgery. All patients had fourth-generation plasma troponin T (TnT) concentrations measured during the first 3 postoperative days. MINS was defined as a TnT of 0.03 ng/mL of higher secondary to ischemia. The objectives of the present study were to determine (i) if MINS is prognostically important in vascular surgical patients, (ii) the clinical characteristics of vascular surgery patients with and without MINS, (iii) the 30-day outcomes for vascular surgery patients with and without MINS, and (iv) the proportion of MINS that probably would have gone undetected without routine troponin monitoring. RESULTS: The incidence of MINS in the vascular surgery patients was 19.1% (95% confidence interval (CI), 15.7%-22.6%). 30-day all-cause mortality in the vascular cohort was 12.5% (95% CI 7.3%-20.6%) in patients with MINS compared with 1.5% (95% CI 0.7%-3.2%) in patients without MINS (P < 0.001). MINS was independently associated with 30-day mortality in vascular patients (odds ratio, 9.48; 95% CI, 3.46-25.96). The 30-day mortality was similar in MINS patients with (15.0%; 95% CI, 7.1-29.1) and without an ischemic feature (12.2%; 95% CI, 5.3-25.5, P = 0.76). The proportion of vascular surgery patients who suffered MINS without overt evidence of myocardial ischemia was 74.1% (95% CI, 63.6-82.4). CONCLUSIONS: Approximately 1 in 5 patients experienced MINS after vascular surgery. MINS was independently associated with 30-day mortality. The majority of patients with MINS were asymptomatic and would have gone undetected without routine postoperative troponin measurement.

Efecto del ejercicio aeróbico en la rigidez vascular en una población sana / Effect of aerobic exercise in vascular stiffness in healthy population

Resumen Introducción: Un estilo de vida saludable es determinante para la salud cardiovascular. Existe controversia en los efectos vasculares benéficos del ejercicio físico. Objetivo: Evaluar el comportamiento de los parámetros de rigidez vascular en una población sana que practica ejercicio aeróbico rutinario en comparación con una población sana sedentaria. Métodos: Estudio de 32 sujetos sanos, pareados por edad y sexo: 12 hombres y 20 mujeres (46,3 ± 9,7 años), en el cual se evaluaron y compararon los parámetros de rigidez arterial (presión sistólica y diastólica braquial, índices de aumentación braquial y central, velocidad de onda de pulso, presión sistólica y diastólica central, y presión de pulso braquial y central). Las mediciones se hicieron con el método no invasivo-oscilométrico, Arteriograph® (TensioMed Budapest Hungría, Ltd.). Resultados: Se compararon los parámetros de rigidez arterial entre los dos grupos (16 sujetos activos vs. 16 sedentarios), y se encontraron diferencias significativas en los siguientes: frecuencia cardiaca de 53,25 ± 8,0 lpm vs. 59,75± 8,6 lpm (p = 0,034), presión arterial diastólica braquial de 70,0 (4,5) mm Hg vs. 77,5 (8,3) mm Hg (p = 0,043), presión arterial diastólica central de 70,0 (4,5) mm Hg vs. 77,5 (8,1) mm Hg (p = 0,043) y velocidad de onda de pulso de 6,70 (1,1) m/s vs. 7,75 (1,1) m/s (p = 0,001). Conclusiones: La actividad física aeróbica rutinaria tiene un efecto benéfico sobre la rigidez vascular en una población sana, a expensas de una disminución significativa de la velocidad de onda de pulso, la frecuencia cardiaca y la presión arterial diastólica (braquial y central). Estos hallazgos ayudan a explicar los beneficios del ejercicio aeróbico sobre el sistema cardiovascular.

Abstract Introduction: A healthy lifestyle is key for cardiovascular health. There is controversy about beneficial vascular effects of physical exercise. Motivation: To assess the behaviour of vascular stiffness parametres in a healthy population group that practices routine aerobic exercise in comparison with another group of healthy population with a sedentary lifestyle. Methods: Study of 32 healthy individuals, paired according to age and gender: 12 men and 20 women (46.3±9.7 years old); the study assessed and compared arterial stiffness parametres (brachial systolic and diastolic blood pressure, brachial and central augmentation index, pulse wave velocity, central systolic and diastolic blood pressure and brachial and central pulse pressure).Measurements were conducted using the noninvasive oscillometric method Arteriograph® (TensioMed Budapest Hungary, Ltd.). Results: Arterial stiffness parametres were compared between both groups (16 active individuals vs. 16 sedentary ones), and the following significant differences were found: heart rate 53.25 ± 8.0 bpm vs. 59.75 ± 8.6 bpm (p = 0.034), brachial diastolic blood pressure of 70.0 (4.5) mmHg vs. 77.5 (8.3) mmHg (p = 0.043), central diastolic blood pressure of 70.0 (4.5) mmHg vs. 77.5 (8.1) mmHg (p = 0.043) and pulse wave velocity of 6.70 (1.1) m/s vs. 7.75 (1.1) m/s (p = 0.001). Conclusions: Routine aerobic exercise has a beneficial effect on vascular stiffness in a healthy population group, at the expense of a significant decrease in pulse wave velocity, heart rate and diastolic blood pressure (both brachial and central). These findings help explain the benefits of aerobic exercise on the cardiovascular system.

Carta al editor: Manual de práctica clínica basado en la evidencia: preparación del paciente para el acto quirúrgico y traslado al quirófano / Letter to the Editor: Evidence based clinical practice manual: Patient preparation for surgery and transfer to the operating room

Letter to the Editor

Estrategias y obstáculos para el desarrollo de la investigación en programas de anestesiología: documento de consenso en Colombia / Strategies and obstacles to research development in anesthesiology programs: consensus document in Colombia

La práctica clínica perioperatoria en Latinoamérica está influenciada por investigación generada y publicada en países desarrollados. Afortunadamente, las condiciones económicas cada vez más favorables para la ciencia en los países en vías de desarrollo, sumado al incremento en la visibilidad de nuestras publicaciones científicas, han desencadenado un incremento en el interés por mejorar los estándares de la calidad de la investigación local y a su vez en los trabajos de grado que se generan durante los estudios de posgrado en anestesiología. El presente documento es el resultado de la participación y discusión activa de los expositores y asistentes al evento: «Simposio de investigaciones en Anestesia: El camino para participar en la sociedad del conocimiento¼, organizado por la Sociedad Antioqueña de Anestesiología y Reanimación (SADEA) y la Sociedad Colombiana de Anestesiología y Reanimación (SCARE) en el año 2011. El objetivo del documento es plantear estrategias para ajustar, planificar y mejorar los procesos de investigación, así como la creación y la divulgación del conocimiento generado en anestesiología, medicina del dolor y cuidado intensivo para Colombia y países afines. Incluimos recomendaciones para los programas de posgrado, las instituciones prestadoras de salud y sociedades de anestesiología.

Perioperative clinical practice in Latin America is influenced by research developed and published in developed countries. Fortunately, the increasingly favorable economic conditions for science in the developing countries, in addition to the heightened visibility of our scientific publications has triggered greater interest in improving the quality standards of local research and of the graduate theses generated in the course of graduate studies in anesthesiology. This document is the result of the active participation and discussion among the speakers attending the «Symposium on Research in Anesthesia: the path to participation in the society of knowledge¼, organized by the Society of Anesthesiology and Resuscitation of Antioquia (SADEA) and the Colombian Society of Anesthesiology and Resuscitation (SCARE) in 2011. The purpose of the document is to discuss the strategies to adjust, plan and improve the research processes, as well as the creation and dissemination of knowledge generated in Anesthesiology, Pain Medicine and Intensive Care in Colombia and other developing countries. Recommendations have been included for graduate programs, health care providers and the societies of anesthesiology.

Cirugía abierta versus cirugía endovascular en el tratamiento de la patología de la aorta torácica descendente / Open Surgery versus Endovascular Surgery in the Treatment of the Descendent Thoracic Aortic Disease

Introducción: El reparo endovascular de la aorta torácica (REVAT) se ha incrementado en el mundo en los últimos años con relación al abierto. Objetivo: Comparar los resultados clínicos del REVAT frente al reparo abierto en la Fundación Cardio Infantil (Bogotá, Colombia) entre 2002 y 2011. Metodología: Análisis retrospectivo de la cohorte de pacientes sometidos a reparo abierto (grupo 1) en comparación de REVAT (grupo 2). En cada uno de los grupos se evaluó tiempo quirúrgico, tasa de morbilidad, mortalidad, reintervención y estancia hospitalaria. Resultados: Se incluyeron 57 pacientes en el análisis (26 % reparo abierto; 74 % REVAT). Se reintervinieron dos pacientes por endofugas tipo 1 en el grupo 2 y un caso por sangrado en el grupo 1. La mortalidad operatoria fue para el grupo 1 de 20 %, y para el grupo 2, de 2,3 %. El tiempo quirúrgico fue de 398 ± 180 min (grupo 1) versus 85,5 ± 35 min (grupo 2 (p = 0,0001) y el tiempo de estancia hospitalaria promedio fue de 9,8 días (grupo 1) y 5,3 días (grupo 2) [p = 0,01]). El tiempo promedio de seguimiento fue 4,8 ± 3,1 años. Conclusiones: El REVAT parece ofrecer menor morbilidad, mortalidad, tiempo quirúrgico y estancia hospitalaria respecto al reparo abierto, aunque las poblaciones de pacientes incluidos no fueron estrictamente comparables. Se requieren nuevos análisis en un diseño prospectivo, idealmente aleatorizado para documentar los beneficios a largo plazo de este tipo de reparo...

Introduction: Thoracic Endovascular Aortic Repair(TEVAR) has increased worldwide morethan open repair in the last few years. Objective:To compare clinical outcomes of TEVARversus open surgery at Fundación Cardio Infantil(Bogota, Colombia), between 2002 and 2011.Methods: Retrospective analysis of the cohort ofpatients with open repair (group 1) in comparisonto TEVAR (group 2). In each group, surgicaltime, morbidity rates (infection, hemorrhage,medular ischemia, cerebrovascular event, andpostoperative renal failure), mortality, reintervention,and hospital stay were evaluated. For comparisonsa univariate analysis was used, being a p< 0.05 statistically significant. Results: 57 patientswere included (26 % open repair; 74 % TEVAR).Two type 1 endoleaks on group 2 and 1 bleedingpatient in group 1 required a second surgery. Surgicalmortality was 20 % in group 1, and 2.3 % ingroup 2); surgical time was 398 ± 180 (group 1)versus 85.5 ± 35 min (group 2) (p = 0.0001); andhospital stay was 9,8 days (group 1) and 5.3 days(group 2). Average follow-up time was 4.8 ± 3.1years. Conclusions: TEVAR may be associatedwith less morbidity, mortality, surgical time, andhospital stay than open repair, although the populationsincluded were not strictly comparable.New, prospective studies, ideally randomized,are needed to support the long term benefits ofthis type of repair...

Risk factors associated with postoperative seizures in patients undergoing cardiac surgery who received tranexamic acid: a case-control study.

Antifibrinolytic agents are used during cardiac surgery to minimize bleeding and reduce exposure to blood products. Several reports suggest that tranexamic acid (TA) can induce seizure activity in the postoperative period. To examine factors associated with postoperative seizures in patients undergoing cardiac surgery who received TA. University-affiliated hospital. Case-control study. Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) between January 2008 and December 2009 were identified. During this time, all patients undergoing heart surgery with CPB received TA. Cases were defined as patients who developed seizures that required initiation of anticonvulsive therapy within 48 h of surgery. Exclusion criteria included subjects with preexisting epilepsy and patients in whom the convulsive episode was secondary to a new ischemic lesion on brain imaging. Controls who did not develop seizures were randomly selected from the initial cohort. From an initial cohort of 903 patients, we identified 32 patients with postoperative seizures. Four patients were excluded. Twenty-eight cases and 112 controls were analyzed. Cases were more likely to have a history of renal impairment and higher preoperative creatinine values compared with controls (1.39 ± 1.1 vs. 0.98 ± 0.02 mg/dL, P = 0.02). Significant differences in the intensive care unit, postoperative and total lengths of stay were observed. An association between high preoperative creatinine value and postoperative seizure was identified. TA may be associated with the development of postoperative seizures in patients with renal dysfunction. Doses of TA should be reduced or even avoided in this population.

Caffeine's Vascular Mechanisms of Action.

Caffeine is the most widely consumed stimulating substance in the world. It is found in coffee, tea, soft drinks, chocolate, and many medications. Caffeine is a xanthine with various effects and mechanisms of action in vascular tissue. In endothelial cells, it increases intracellular calcium stimulating the production of nitric oxide through the expression of the endothelial nitric oxide synthase enzyme. Nitric oxide is diffused to the vascular smooth muscle cell to produce vasodilation. In vascular smooth muscle cells its effect is predominantly a competitive inhibition of phosphodiesterase, producing an accumulation of cAMP and vasodilation. In addition, it blocks the adenosine receptors present in the vascular tissue to produce vasoconstriction. In this paper the main mechanisms of action of caffeine on the vascular tissue are described, in which it is shown that caffeine has some cardiovascular properties and effects which could be considered beneficial.

Comparison of two protective lung ventilatory regimes on oxygenation during one-lung ventilation: a randomized controlled trial.

BACKGROUND: The efficacy of protective ventilation in acute lung injury has validated its use in the operating room for patients undergoing thoracic surgery with one-lung ventilation (OLV). The purpose of this study was to investigate the effects of two different modes of ventilation using low tidal volumes: pressure controlled ventilation (PCV) vs. volume controlled ventilation (VCV) on oxygenation and airway pressures during OLV. METHODS: We studied 41 patients scheduled for thoracoscopy surgery. After initial two-lung ventilation with VCV patients were randomly assigned to one of two groups. In one group OLV was started with VCV (tidal volume 6 mL/kg, PEEP 5) and after 30 minutes ventilation was switched to PCV (inspiratory pressure to provide a tidal volume of 6 mL/kg, PEEP 5) for the same time period. In the second group, ventilation modes were performed in reverse order. Airway pressures and blood gases were obtained at the end of each ventilatory mode. RESULTS: PaO2, PaCO2 and alveolar-arterial oxygen difference did not differ between PCV and VCV. Peak airway pressure was significantly lower in PCV compared with VCV (19.9 ± 3.8 cmH2O vs 23.1 ± 4.3 cmH2O; p < 0.001) without any significant differences in mean and plateau pressures. CONCLUSIONS: In patients with good preoperative pulmonary function undergoing thoracoscopy surgery, the use of a protective lung ventilation strategy with VCV or PCV does not affect the oxygenation. PCV was associated with lower peak airway pressures.

Intubación orotraqueal sin relajante muscular: propofol o etomidato en combinación con remifentanilo / Orotracheal Intubation without the use of muscle relaxant: propofol or etomidate in combination with remifentanil

Introducción. El remifentanilo en combinación con propofol provee adecuadas condiciones para la intubación orotraqueal sin relajante neuromuscular. Otros agentes inductores no han sido adecuadamente evaluados. El propósito del estudio fue evaluar las condiciones de intubación y los cambios hemodinámicos tras la inducción anestésica con remifentanilo-propofol o remifentanilo- etomidato. Métodos. En este estudio prospectivo, doble ciego y aleatorio, participaron 90 pacientes con clasificación ASA I/II. Recibieron 0,03 mg/kg de midazolam y 7 ml/kg de lactato de Ringer, y posteriormente, 3 mg/kg de remifentanilo seguidos de 1 mg/kg de lidocaína. A continuación, se distribuyeron en forma aleatoria en los siguientes grupos de pacientes: los que recibieron 2 mg/kg de propofol (grupo propofol, n=29), 0,3 mg/ kg de etomidato (grupo etomidato 3, n=31) o 0,4 mg/kg de etomidato (grupo etomidato 4, n=30). Después se realizó laringoscopia e intubación orotraqueal. Las condiciones para la intubación se evaluaron utilizando un sistema cualitativo de puntaje. Se registraron la presión arterial media y la frecuencia cardiaca previa a la inducción, posterior a la inducción, inmediatamente después de la intubación y cada minuto hasta 5 minutos después de la intubación. Resultados. Tres pacientes del grupo etomidato 3 y dos del grupo etomidato 4 no pudieron ser intubados en el primer intento. Se alcanzaron condiciones clínicamente aceptables de intubación en 100%, 74% y 80%, en los grupo propofol, etomidato 3 y etomidato 4, respectivamente (p=0,016). El descenso en la presión arterial media fue significativamente mayor en el grupo propofol comparado con el grupo etomidato 3. Conclusiones. Para la intubación orotraqueal sin relajante neuromuscular, el uso de remifentanilo-propofol es superior al de remifentanilo-etomidato, 0,3 mg/kg o 0,4 mg/kg. Con 0,3 mg/kg de etomidato se obtiene un mejor perfil hemodinámico.

Introduction: Remifentanil followed by propofol provides adequate conditions for tracheal intubation without using muscle relaxants. Other hypnotic drugs have not been thoroughly evaluated in this regard. The purpose of this study was to assess intubating conditions and cardiovascular changes after induction of anesthesia with remifentanil-propofol or. Methods: 90 ASA I/II patients were enrolled in this random, prospective, double-blind study. Subjects received 0.03 mg/kg of midazolam followed by a 7 ml/kg infusion of RingerLs lactate. After that, 3 ƒÊg/kg of remifentanil were injected followed by lydocaine, 1 mg/kg. Then, patients received either propofol (2 mg/ kg) (Propofol Group, n= 29), or etomidate (0.3 mg/kg) (Etomidate 3 Group, n=31) or etomidate (0.4 mg/kg) (Etomidate 4 Group, n=30). Subsequent laryngoscope and intubation were performed. Intubating conditions were assessed using a quality scoring system. Mean arterial pressure and heart rates pre-induction, post-induction were recorded immediately after intubation and every 1 to 5 minutes after intubation. Results: Three patients in the etomidate 3 Group and two patients in the etomidate 4 Group were not able to beintubated in the first attempt. Clinically acceptable intubating conditions were observed in 100%, 74%, 80% in the Propofol, Etomidate 3 and etomodate 4 groups, respectively (p=0.01 6). The decrease in mean arterial pressure was significantly higher in the propofol group as compared to the etomidate 3 group (p<0.05). Conclusions: The use of lydocaine-remifentanil-propofol for tracheal intubation without muscle relaxants is superior to 0.3 or 0.4 mg/kg lydocaine-remifentanil plus etomidate. However, etomidate 0.3 mg/kg produces a better hemodynamic profile when compared to propofol.

The role of potassium channels in the vasodilatory effect of caffeine in human internal mammary arteries.

There is little information about the direct effect of caffeine in human blood vessels. The purpose of this study was to evaluate the direct vascular effect of caffeine on human internal mammary artery (IMA) and the involvement of potassium channels in this response. Segments of IMA were obtained from 29 patients who underwent coronary artery bypass graft surgery. They were cut into rings, suspended between two wire hooks in organ bath chambers and constricted submaximally with norepinephrine. Caffeine (3.16x10(-9) to 10(-4) mol/L) was added in a cumulative fashion to rings with or without functional endothelium and concentration response curves were constructed. The response to caffeine was also evaluated after incubation with adenosine 3',5'-triphosphate (ATP)-dependent potassium channel blocker glibenclamide, voltage-dependent potassium channel blocker 4-aminopyridine and large-conductance calcium-activated potassium channel inhibitor tetraethylammonium. Caffeine produced a potent, concentration-dependent relaxation of IMA. The relaxant responses did not differ significantly between endothelium-intact and endothelium-denuded preparations. Incubation with different potassium channel inhibitors (glibenclamide, 4-aminopyridine and tetraethylammonium) did not cause significant alterations in the relaxant responses to caffeine. These results suggest that the vasodilatory response to caffeine in human IMA is independent of endothelial function and is not mediated by potassium channels.

Comparison of spinal anesthesia with combined sciatic-femoral nerve block for outpatient knee arthroscopy.

STUDY OBJECTIVE: To compare spinal anesthesia and combined sciatic-femoral nerve block for outpatient knee arthroscopy. DESIGN: Prospective, randomized, controlled study. SETTING: Postoperative recovery area at a university-affiliated medical center. PATIENTS: 50 ASA physical status I and II adult outpatients undergoing arthroscopic knee surgery. INTERVENTIONS: Study subjects were equally divided (n = 25 each) into spinal and sciatic-femoral groups. Spinal group patients received spinal anesthesia with 7.5 mg of 0.5% hyperbaric bupivacaine. Sciatic-femoral group patients received combined sciatic-femoral nerve blocks using a mixture of 20 mL of lidocaine 2% plus 20 mL of bupivacaine 0.5%. MEASUREMENTS: Times including that from arrival in the operating room to readiness for surgery, duration of surgery, recovery time, and patient satisfaction were recorded. Analgesia and occurrence of adverse events also were recorded. MAIN RESULTS: No significant differences between the two groups were found for any of the study measurements of recovery. After discharge, postoperative pain differed significantly between groups only at 6 hours (P < 0.002). Patient satisfaction was high with both techniques. CONCLUSIONS: Combined sciatic-femoral nerve block for outpatient arthroscopic knee surgery offers satisfactory anesthesia, with a clinical profile similar to that of low-dose spinal anesthesia. Sciatic-femoral nerve blocks are associated with significantly lower pain scores during the first 6 postoperative hours.

[In vitro effect of caffeine on internal mammary artery rings used in cardiac revascularization surgery]. / Acción in vitro de la cafeína en anillos de arteria mamaria interna utilizada en cirugía de revascularización cardiaca.

INTRODUCTION: The vasodilator effect of caffeine in animal models arteries has been demonstrated previously. However, studies with the same methodology using human arteries in vitro have not been performed. OBJECTIVES: The in vitro vasoactive effects of caffeine was evaluated on human internal mammary arteries. MATERIALS AND METHODS: Internal mammary artery rings were used (n = 20). Endothelial function was evaluated with acetylcholine at a concentration of 3.16 x 10 -6 M, nitroglycerine at cumulative concentrations of 10 -11 M to 10 -4 M and caffeine with cumulative concentrations of 10 -8 M to 10 -4 M. RESULTS: Nitroglycerin produced a maximum relaxation percentage of 87.4 +/- 12.3%, caffeine a percentage of 86.9 +/- 21.0% in arteries with functional endothelium, and of 71.6 +/- 28.6% in arteries with endothelial dysfunction. No differences were detected among the three groups ( p=0.289). Similarly, no differences were found between EC 50 in arteries with functional endothelium (1.66 x 10 -5 +/-1.57 x 10 -5 M) and dysfunctional arteries (7.8 x 10 -5 +/-14.6 x 10 -5 M). Nitroglycerine proved more potent than caffeine (EC 50 = 4.3 x 10 -9 +/-4.4 x 10 -9 M) ( p=0.013). CONCLUSIONS: Although nitroglycerin was a more potent vasodilator, caffeine had a strong arterial vasodilator effect regardless of endothelial function in human arteries.

Acción in vitro de la cafeína en anillos de arteria mamaria interna utilizada en cirugía de revascularización cardiaca / In vitro effect of caffeine on internal mammary artery rings used in cardiac revascularization surgery

Introducción. El efecto vasodilatador de la cafeína en las arterias de modelos animales ya ha sido demostrado. Se desconocen estudios con la misma metodología in vitro utilizando arterias humanas. Objetivos. Evaluar los efectos vasoactivos in vitro de la cafeína en la arteria mamaria interna de humanos. Materiales y métodos. Se utilizaron 80 anillos de arteria mamaria interna (n=20 pacientes). La funcionalidad del endotelio se evaluó con acetilcolina a una concentración de 3,16x10 -6 M, de nitroglicerina con dosis acumulativas de 10 –11 M a 10 –4 M y de cafeína con concentraciones acumulativas de 10 –8 M a 10 –4 M. Resultados. La nitroglicerina indujo un porcentaje máximo de relajación de 87,4±12,3 por ciento, la cafeína, de 86,9±21,0 por ciento en arterias con endotelio funcional y de 71,6±28,6 por ciento en arterias con disfunción endotelial. No se encontraron diferencias entre los tres grupos ( p=0,289). Tampoco se encontraron diferencias en la EC 50 en arterias con endotelio funcional (1,66x10 -5 ±1,57x10 -5 M) y arterias disfuncionales (7,75x10 -5 ±14,64x10 -5 M). La nitroglicerina resultó más potente que la cafeína (EC 50 = 4,30x10 -9 ±4,35x10 -9 M) ( p=0,013). Conclusiones. Aunque la nitroglicerina fue un vasodilatador más potente, la cafeína tuvo un fuerte efecto vasodilatador arterial in vitro independientemente de la funcionalidad del endotelio en arterias humanas.